1. Field of the Invention
The present invention relates generally to compositions and methods for improving the phosphatation clarification of sugar liquors and syrups.
2. Related Art
Industry standards in the clarification of sugar liquors and syrups include a phosphatation or carbonatation process (Cane Sugar Handbook, 12th. Ed., pgs. 454-455). In the phosphatation clarification process, lime and phosphoric acid are added to the sugar liquors or syrups to form a calcium phosphate floc. The formation of the floc entraps impurities within and around the floc matrix, and air is sparged into the liquor or syrup to float the flocs and the impurities removed therein. A floating scum, containing the flocs and entrapped impurities, is formed at the top of the clarifier tank. The scum is removed from the top of the clarifier tank, and the purified liquor or syrup is taken from the bottom portion of the clarifier tank. Polymer flocculants and coagulants, such as those exemplified by polyacrylamide flocculants and quaternary ammonium coagulants, may be beneficially added to enhance the phosphatation process (Cane Sugar Handbook, 12th. Ed., pgs. 454-455). Additional clarity may be imparted to the sugar liquor and syrups after the phosphatation clarification; this can be achieved with deep-bed sand filtration and/or additional decolorization processes such as treating the clarified liquor with powder activated carbon (PAC) and diatomaceous earth (DE) filtration, or passing the clarified liquor through Granular Activated Carbon (GAC) or Ion-Exchange Resin (IER) columns.
Recent processes for sugar liquor and syrup clarification include those exemplified by U.S. Pat. No. 5,281,279 to Gil et al. This patent describes a process for producing refined sugar from raw sugar juices by treating raw sugar juice with a flocculent that can be lime, a source of phosphate ions, polyelectrolyte, and combinations thereof. The treated raw juice is concentrated by evaporation to form a syrup, with a subsequent treatment by flocculent, then filtered, then decolorized and de-ashed using ion-exchange resin.
In U.S. Pat. No. 4,247,340, Cartier claims a process for purifying impure sugar solutions, including simultaneous decolorization and clarification, comprising contacting the impure sugar solutions with submicroscopic ion-exchange resin in the forms of approximately spherical beads having diameters from about 0.01 to 1.5 microns, followed by separation of the ion-exchange resin from the sugar solution. The ion-exchange resin particles may be separated in the form of a floc formed either from impurities in the impure sugar solution, or by adding sufficient flocculating agent in the sugar solution to flocculate all of the resin particles.
Another example of sugar clarification for sugar bearing juices and related products includes that described in U.S. Pat. No. 5,262,328 to Clarke et al. The composition is a dry, powdered admixture of aluminum chloride hydroxide, lime, and activated bentonite. The composition may also include a polymer flocculating agent, such as a polyacrylamide.